Erin Chack (left) and her mom, Joanne Chack, at Erin’s college graduation.Courtesy of Erin Chack

Erin Chack should have been celebrating. After six months of exhausting, hair-loss-inducing chemotherapy for Hodgkin’s lymphoma, she’d just had her first checkup and was in remission. She was free.

But another appointment hovered like a dark cloud. It was taking place the very same day a few floors down, where Chack’s mom, Joanne Chack, was due to start her own round of chemo after being diagnosed with the very same cancer less than a year after Erin’s diagnosis.

courtesy of Razorbill

“I just remember feeling very angry,” says Erin, now 27, to The Post, recalling when she heard about her mother’s diagnosis, a story she also shares in her just-released essay collection “This Is Really Happening” (Razorbill, out Tuesday). Then 20 years old, Erin had just returned to Boston University to begin her sophomore year of college, after taking a break to undergo treatment. Her mom was 54.

“I thought, God, I know exactly how s–tty this is going to be [for her],” says Erin, who lives in Astoria and works as a senior writer at Buzzfeed. “And now I have to watch her go through all the stuff I’d hoped I’d forget about.”

Having a close family member who has had lymphoma does increase a person’s risk of developing the cancer, but the risk is still extremely low.

As hard as it was to watch her mom go through cancer, it opened up fresh wounds for Erin, too.

“When I went through [treatment], there were times when it was really hard, but I didn’t let on that it was,” Erin says. “[My mom’s] a little more emotional, and she would be a lot more vocal about stuff that was bothering her.”

‘Our whole town rallied around me to help me pay my bills, and they were there emotionally and financially. And now it was like, OK, we need to ask for help again.’

- Erin Chack

It was also hard for her family, she says, that they needed to ask their friends for support once again.

“Our whole town rallied around me to help me pay my bills, and they were there emotionally and financially,” she says. “And now it was like, OK, we need to ask for help again.”

Mother and daughter are now healthy and cancer-free, and supporting one another in ways they never expected.

Joanne cajoled Erin into seeing a therapist, for instance, as part of a free program at Memorial Sloan Kettering where they both received treatment. “She started going, and I had never thought I should do that,” Erin says. But she made an appointment at her mom’s request, and hasn’t looked back.

“Now my therapist at Sloan is like my lifeline,” she says. “I love her so much.”

And Erin, who bikes to work and goes on runs around the city, is making sure her mom stays active. “We help each other out,” she says.